题目

阅读下面材料，在空白处填入适当的内容（1个单词）或括号内单词的正确形式。The world’s longest sea bridge, the Hong Kong-Zhuhai-Macau Bridge, links Hong Kong and Macau to mainland China. 【1】 took over a decade to construct. A few artificial islands were built in the Pearl River Delta 【2】 (provide) the supports for the bridge. There is 【3】 6.7-kilometre underwater tunnel in the middle of the bridge, 【4】 allows ships to sail through the Delta. The bridge will 【5】 (great) cut the time it takes to travel from mainland China to Hong Kong and Maca（6分）完成下列反应的离子方程式：（1）向NaHSO4溶液中逐滴加入Ba(OH)2溶液，使原溶液中的SO42—恰好完全沉淀：                                                      （2）向明矾溶液中逐滴加入Ba(OH)溶液，当Al3+恰好全部沉淀时：                                （3）向Ca(HCO3) 2溶液中加入过量的NaOH溶液：